Commit c5d1686b authored by Felix Fietkau's avatar Felix Fietkau Committed by Johannes Berg
Browse files

mac80211: add a function for running rx without passing skbs to the stack 



This can be used to run mac80211 rx processing on a batch of frames in NAPI
poll before passing them to the network stack in a large batch.
This can improve icache footprint, or it can be used to pass frames via
netif_receive_skb_list.

Signed-off-by: default avatarFelix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20200726110611.46886-1-nbd@nbd.name


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent cb17ed29

include/net/mac80211.h

+25 −0
Original line number Diff line number Diff line
@@ -4360,6 +4360,31 @@ void ieee80211_free_hw(struct ieee80211_hw *hw); 
 */

void ieee80211_restart_hw(struct ieee80211_hw *hw);



/**

 * ieee80211_rx_list - receive frame and store processed skbs in a list

 *

 * Use this function to hand received frames to mac80211. The receive

 * buffer in @skb must start with an IEEE 802.11 header. In case of a

 * paged @skb is used, the driver is recommended to put the ieee80211

 * header of the frame on the linear part of the @skb to avoid memory

 * allocation and/or memcpy by the stack.

 *

 * This function may not be called in IRQ context. Calls to this function

 * for a single hardware must be synchronized against each other. Calls to

 * this function, ieee80211_rx_ni() and ieee80211_rx_irqsafe() may not be

 * mixed for a single hardware. Must not run concurrently with

 * ieee80211_tx_status() or ieee80211_tx_status_ni().

 *

 * This function must be called with BHs disabled and RCU read lock

 *

 * @hw: the hardware this frame came in on

 * @sta: the station the frame was received from, or %NULL

 * @skb: the buffer to receive, owned by mac80211 after this call

 * @list: the destination list

 */

void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *sta,

		       struct sk_buff *skb, struct list_head *list);



/**

 * ieee80211_rx_napi - receive frame from NAPI context

 *

net/mac80211/ieee80211_i.h

+1 −1
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ enum ieee80211_rx_flags { 
};



struct ieee80211_rx_data {

	struct napi_struct *napi;

	struct list_head *list;

	struct sk_buff *skb;

	struct ieee80211_local *local;

	struct ieee80211_sub_if_data *sdata;

net/mac80211/rx.c

+38 −22
Original line number Diff line number Diff line
@@ -2578,8 +2578,8 @@ static void ieee80211_deliver_skb_to_local_stack(struct sk_buff *skb, 
		memset(skb->cb, 0, sizeof(skb->cb));



		/* deliver to local stack */

		if (rx->napi)

			napi_gro_receive(rx->napi, skb);

		if (rx->list)

			list_add_tail(&skb->list, rx->list);

		else

			netif_receive_skb(skb);

	}
@@ -3869,7 +3869,6 @@ void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid) 
		/* This is OK -- must be QoS data frame */

		.security_idx = tid,

		.seqno_idx = tid,

		.napi = NULL, /* must be NULL to not have races */

	};

	struct tid_ampdu_rx *tid_agg_rx;
@@ -4479,8 +4478,8 @@ static bool ieee80211_invoke_fast_rx(struct ieee80211_rx_data *rx, 
	/* deliver to local stack */

	skb->protocol = eth_type_trans(skb, fast_rx->dev);

	memset(skb->cb, 0, sizeof(skb->cb));

	if (rx->napi)

		napi_gro_receive(rx->napi, skb);

	if (rx->list)

		list_add_tail(&skb->list, rx->list);

	else

		netif_receive_skb(skb);
@@ -4547,7 +4546,7 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx, 
static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw,

					 struct ieee80211_sta *pubsta,

					 struct sk_buff *skb,

					 struct napi_struct *napi)

					 struct list_head *list)

{

	struct ieee80211_local *local = hw_to_local(hw);

	struct ieee80211_sub_if_data *sdata;
@@ -4562,7 +4561,7 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, 
	memset(&rx, 0, sizeof(rx));

	rx.skb = skb;

	rx.local = local;

	rx.napi = napi;

	rx.list = list;



	if (ieee80211_is_data(fc) || ieee80211_is_mgmt(fc))

		I802_DEBUG_INC(local->dot11ReceivedFragmentCount);
@@ -4670,8 +4669,8 @@ static void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, 
 * This is the receive path handler. It is called by a low level driver when an

 * 802.11 MPDU is received from the hardware.

 */

void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,

		       struct sk_buff *skb, struct napi_struct *napi)

void ieee80211_rx_list(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,

		       struct sk_buff *skb, struct list_head *list)

{

	struct ieee80211_local *local = hw_to_local(hw);

	struct ieee80211_rate *rate = NULL;
@@ -4762,13 +4761,6 @@ void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta, 


	status->rx_flags = 0;



	/*

	 * key references and virtual interfaces are protected using RCU

	 * and this requires that we are in a read-side RCU section during

	 * receive processing

	 */

	rcu_read_lock();



	/*

	 * Frames with failed FCS/PLCP checksum are not returned,

	 * all other frames are returned without radiotap header
@@ -4776,23 +4768,47 @@ void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta, 
	 * Also, frames with less than 16 bytes are dropped.

	 */

	skb = ieee80211_rx_monitor(local, skb, rate);

	if (!skb) {

		rcu_read_unlock();

	if (!skb)

		return;

	}



	ieee80211_tpt_led_trig_rx(local,

			((struct ieee80211_hdr *)skb->data)->frame_control,

			skb->len);



	__ieee80211_rx_handle_packet(hw, pubsta, skb, napi);



	rcu_read_unlock();

	__ieee80211_rx_handle_packet(hw, pubsta, skb, list);



	return;

 drop:

	kfree_skb(skb);

}

EXPORT_SYMBOL(ieee80211_rx_list);



void ieee80211_rx_napi(struct ieee80211_hw *hw, struct ieee80211_sta *pubsta,

		       struct sk_buff *skb, struct napi_struct *napi)

{

	struct sk_buff *tmp;

	LIST_HEAD(list);





	/*

	 * key references and virtual interfaces are protected using RCU

	 * and this requires that we are in a read-side RCU section during

	 * receive processing

	 */

	rcu_read_lock();

	ieee80211_rx_list(hw, pubsta, skb, &list);

	rcu_read_unlock();



	if (!napi) {

		netif_receive_skb_list(&list);

		return;

	}



	list_for_each_entry_safe(skb, tmp, &list, list) {

		skb_list_del_init(skb);

		napi_gro_receive(napi, skb);

	}

}

EXPORT_SYMBOL(ieee80211_rx_napi);



/* This is a version of the rx handler that can be called from hard irq